Cellulitis is an acute spreading inflammation of the skin and subcutaneous tissues characterised by pain, warmth, swelling and erythema. Cellulitis typically only occurs in one leg.
Assessment of a patient with cellulitis
Cellulitis can be difficult to diagnose and to distinguish from other causes of inflammation in the legs but cellulitis most commonly affects one leg only. If the patient presents with bilateral ‘red legs’, it is likely to be associated with venous hypertension / insufficiency (Refer to swollen legs and feet section of the website and / or haemosiderin staining page).
- Some episodes are accompanied by severe systemic upset, with high fever and rigors; others are milder, with minimal or no fever
- Increased swelling of the affected area may occur
- Inflammatory markers (CRP, ESR) may be raised
Your initial assessment should include a baseline record to include the following:
- Extent and severity of rash – if possible, mark and date the edge of the erythema (this may be difficult in lymphoedema as the rash is often blotchy)
- Level of systemic upset
- Note history of repeated cellulitis, often a sign of unmanaged swelling
- CRP/ESR/white cell count – these may be helpful in diagnosis and monitoring of treatment
- Microbiology of any cuts or breaks in the skin – this should be considered before antibiotics are started.
You should decide whether hospital admission is required by:
- The level of systemic upset and any signs of septicaemia
- Whether symptoms are worsening despite treatment
What does cellulitis look like?
Treatment of cellulitis – this includes prevention of recurrence
Prompt treatment is essential to avoid further damage to the lymphatics of the affected part as this may predispose to repeated attacks.
Antibiotic therapy is required to treat cellulitis. As with any infection, the choice of antibiotic prescribed is determined by the presumed bacteria. This is more difficult for cellulitis as rate of positive blood culture is known to be low.
Your Trust and Clinical Commissioning Groups (CCG) is likely to have its own antibiotic prescribing guidelines but there are also guidelines available which have been developed specifically for cellulitis (PDF download) and the management of cellulitis in people with lymphoedema (PDF download)
When prescribing antibiotics, you should also consider drug allergies, specifically to penicillin and drug interactions, particularly when prescribing macrolides.
If there is no response or a poor response (inflammation is not resolving) to oral antibiotics after 48 hours of treatment, then you should consider prescribing second line antibiotic therapy. If signs or symptoms deteriorate despite oral antibiotics, then you should consider hospital admission for intravenous antibiotics.
Antibiotics should be continued until all signs of acute inflammation have resolved. For the treatment of cellulitis in people with leg swelling this may mean taking antibiotics for 1-2 months. It is recommended that the course of antibiotics should be for no less than 14 days from the time a definite clinical response is observed.
Skin changes e.g. discolouration / staining may persist for months or longer following severe cellulitis and do not necessarily require ongoing antibiotics.
Bed rest and elevation
Bed rest and elevation of the affected part is essential. When inflammation is sufficiently reduced, normal levels of exercise may resume. A return to work depends on the patient’s occupation and there being no deterioration when normal levels of exercise are established.
You should advise your patient to avoid compression garments during the acute attack. These should be replaced as soon as the affected area is comfortable enough to tolerate them though.
Remember that cellulitis is commonly due to unmanaged oedema so the limb will benefit from a swift return to this important therapy. Compression bandaging even in reduced form might be tolerated; the patient should have access as soon as possible to the anti-inflammatory effects of compression therapy to resolve the cellulitis quickly and to augment the antibiotics. Simple analgesics may help your patient to tolerate their compression.
You may need to check the fit of the compression garment as the area may become more swollen after an episode of cellulitis.
You should advise your patient to take analgesia. Paracetamol is currently recommended as the first line choice of analgesia as there are concerns that NSAIDS prescribed during an episode of infection may increase the risk of necrotising fasciitis.
Reducing the risk of recurrence
The risk of further attacks of cellulitis in lymphoedema is high. Risk factors for recurrence of cellulitis in lymphoedema include:
- Cracked, macerated, inter-digital skin
- Open wounds including leg ulcers and weeping lymphangiectasia (leaking lymph blisters on the skin surface)
Check for and treat any possible underlying fungal infection and this will help to prevent recurrence.
Inter-digital fungus should be treated with application of terbinafine cream daily for two weeks.
Decongestive lymphatic therapy (DLT)
Lymphoedema treatment (decongestive lymphatic therapy – DLT) is thought to reduce the frequency of attacks.
Prophylactic antibiotic therapy
Patients who have had an attack of cellulitis should carry a 2 week supply of antibiotics with them particularly when away from home for any length of time, e.g. on holiday. You should advise your patient to start antibiotics immediately if they observe familiar symptoms of cellulitis develop, but to seek a medical opinion as soon as possible.
You should consider antibiotic prophylaxis in patients who have two or more attacks of cellulitis per year. It may not be possible to fully prevent further episodes of cellulitis even with prophylactic antibiotics. However, there may be a reduction in the frequency of cellulitis and / or the severity of episodes.
Following two years of successful prophylaxis, discontinuation should be considered, particularly if the risk factors have been successfully addressed. However, if there are ongoing significant risk factors, continuing prophylaxis should be considered. Prophylaxis may need to be lifelong if relapse occurs after prophylactic antibiotics are discontinued.
Clinical guidelines for cellulitis
These guidelines give you a useful overview and more detailed information about cellulitis within the context of lymphoedema.
- British Lymphology Society Consensus Document of the Management of Cellulitis (PDF download)
- CREST Guidelines On The Management of Cellulitis In Adults (PDF download)
Research surrounding cellulitis
Research evidence to support practice includes a number of systematic reviews about venous leg ulceration.
The Cochrane Library publishes systematic reviews about the effectiveness of many treatments for cellulitis.
Publications & Evidence for cellulitis
We’ve carefully curated resources to help in your everyday work.
Patient information for cellulitis
The patients, family and friends section has lots of useful, accessible information for your patients.
Dowload a patient information leaflet as a pdf to print
The British Lymphology Society (BLS) is a dynamic and innovative body providing a strong professional voice and support for those involved in the care and treatment of people with lymphoedema and related lymphatic disorders, including lipoedema.
Find out more on the British Lymphology Society website
Lymphoedema Support Network (LSN) is a national UK charity which provides information and support to people with lymphoedema.
020 7351 0990
Find out more on the Lymphoedema Support Network website
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